There is another elder effect. Elders are repositories of experience over
a time span which allows them to have survival knowledge that comes as a
cycle, like drought. They see variations of difficult births, crop
productions and their effects, tactics in war in different situations, and
other such information.
Quoted message said:Yes. This is due to the fact that humans take an extremely long time to
reach reproductive maturity, and are helpless for a lot of that time. In
order for an individual to "propagate his genes" it's necessary not only
for him to reproduce, but for his kids to survive long enough to be able to
reproduce themselves, which for most of human history was *at least* 14 or
15 years. Therefore, there's selective pressure to survive not just long
enough to reproduce, but long enough for one's kids to grow up. That
pressure doesn't exist in species with shorter generation times.